This invention relates to incandescent lamps and, in particular, to an incandescent lamp having an internal switch for keeping at least one filament of the lamp in an on condition after the main circuit to the lamp is opened.
In the prior art, a number of lighting systems have been proposed for buildings and automobiles in which a lamp is temporarily kept lighted until the user has left the premises or otherwise no longer needs the light. The difficulty with prior art solutions to the problem is that additional wiring or circuitry is necessary, which may not be aesthetically pleasing, practical, or the least costly solution.